The present invention relates to a backlight module, and in particular to a backlight module with thermal dissipation fins.
In a liquid crystal display, a backlight module is generally utilized as a light source. With different positions of light sources, the backlight module can be divided into a side-light and a direct backlight module.
FIG. 1 is an exploded perspective view of a conventional direct type backlight module. In FIG. 1, a direct backlight module 10 includes a back bezel 11, a reflector 12, a diffuser 15, two fixing rims 13a and 13b, and a plurality of lamps 14 as light sources. The reflector 12 is disposed on the back bezel 11 and comprises a surface with high reflectivity to increase illumination of the backlight module 10. Conventional direct backlight modules utilize cold cathode fluorescent lamps as light sources. To assemble the backlight module 10, the lamps 14 pass through the holes 132 of the fixing rims 13a and 13b. Simultaneously, the fixing rims 13a and 13b are fixed on the opposite sides of the back bezel 11 by the hooks 134 engaging with the notches 112. The diffuser 15 is disposed above the reflector 12, covering the opening thereof. Thus, the light provided by the lamps 14 can be completely reflected upward and pass through the diffuser 15, providing required uniform illumination of the large-sized LCD panel.
Furthermore, conventional direct backlight modules 10 may have optical films, such as prism films, of which the descriptions are omitted.
In conventional direct backlight module, the back bezel is aluminum and utilized to absorb lots of heat produced by lamps. The hot air is concentrated at the top portion of the backlight module because of heat convection effect (at the top left side of the back bezel 11 in FIG. 1). Thus, local temperature at the top portion of the backlight module is relatively higher than that at the other portion therein, and high temperature reduces the light emitting efficiency of the lamps and causes non-uniform illumination of the backlight module.